‘Xanadu’: Erin Weaver’s a muse in leg warmers at Signature Theatre

Empty calories don’t seem such a misguided nutritional choice when they’re served to you by a force like Erin Weaver, the vitamin-enriched musical star of Signature Theatre’s “Xanadu,” a jaunty, airheaded 90 minutes of ’80s camp.

Let’s count the threats: She sings. She dances. She roller skates. She accomplishes these tasks with charm and aplomb while gliding across the stage in reverse — and still having enough gas in the tank to belt out the high notes in a dozen pop ditties. In an Australian accent, no less! You might not have been shocked, in fact, if Weaver had played every role in the hyper-slight but delectably silly show — and did it while holding flaming batons and hawking Almond Joys at intermission.

Fortunately, she has able backup for this candy-coated outing, especially in players such as Nova Y. Payton and Sherri L. Edelen, who add their own special sauciness to an entertainment drolly supervised by director-choreographer Matthew Gardiner. On Misha Kachman’s glitzy set, dotted with palm trees and bathed in the prom-night glow of two dozen disco balls, they and the rest of the cast sing their satirical hearts out. As it happens, it takes a whole lot of wind to keep a big wheel of cheese in the air.

For “Xanadu” falls into one of those odd theatrical subgenres. It’s an attempt to make a good stage musical out of a bad movie musical. No, not just bad, actually; one of those minor fiascoes for the ages. The 1980 “Xanadu,” starring Olivia Newton-John (whose film career never recovered from the fallout) and Gene Kelly (Gene Kelly?), told of a destitute album cover-painter played by Michael Beck, obsessed with a young woman (Newton-John) who turns out to be — wait for it — one of the nine Muses from Greek myth, sprung to life from a beach-side mural. The synopsis is the sort that leaves you wondering what they were smoking at the pitch meeting.

Is it possible to spin gold out of polyester? Playwright Douglas Carter Beane (“The Little Dog Laughed”) was determined to find out, crafting a cheeky new book for the stage version that uses familiar tunes from the movie (such as “Magic”) and others from the period (“Evil Woman”) by songwriters Jeff Lynne and John Farrar. The hybrid Beane came up with — which ran for 16 months on Broadway, in 2007-08 — treats the material with both a jaundiced eye and a cockeyed grin. It is first and foremost a sendup of the cultural desert many of us recall as the era for such backward steps for Western civilization as the mullet.

Erin Weaver, with Charlie Brady, is charming as Clio in the hilarious “Xanadu.” (Scott Suchman/Signature Theatre)

In the vein of “Little Shop of Horrors,” “Xanadu” tries to appeal to that reservoir of affection we reserve for the garden of rotten tomatoes. You don’t have to know the movie, but it helps to have a memory of when leg warmers were all the rage and Journey was riding high. To pull off this kind of comedy with the proper doses of exuberance and belief is not that easy, although Payton and Edelen, playing two malicious muses, make it look like a breeze; their rendition of “Evil Woman” lifts the production to a higher, giddier realm.

Sometimes, however, the helium does drain from the proceedings and leadenness begins to assert itself. The problem is underlined in the performance of Charlie Brady, who plays Sonny Malone, the hunky beach-bum artist whose need for inspiration summons Weaver’s Clio.

Brady’s got the lunkhead thing down, but it’s his only gear; he doesn’t seem to be enjoying himself as much as the rest of the cast. (The actors playing six of Clio’s sisters-in-muse-ology are uniformly vibrant.) If Brady were to shed just a bit of what comes across as self-consciousness, more of Sonny’s natural charm would materialize, and the actor would take more confident charge of the stage.

Costume designer Kathleen Geldard drapes the muses in becoming style, and the lighting by Chris Lee adds the needed senses of glitter and luster. (Musical director Gabriel Mangiante works wonders with the four-piece accompaniment.) But the most radiant contribution belongs to Weaver, who, with this performance, sends a message to casting people all over the region: You have a musical, she’s ready to roll.